Liquid sensitometry of photographic emulsion

ABSTRACT

A method of performing liquid sensitometry on a liquid photographic emulsion wherein the photographic emulsion is exposed to radiation and then caused to flow in contact with a developer solution. The photographic emulsion and developer remain in distinct layers in contact with each other. During the period when the developer and emulsion flow together, the emulsion is developed by diffusion and penetration of the developer at the interface between the developer and emulsion. The optical density of the developed emulsion is continuously measured.

United States Patent [1 1 Kato et al. Dec. 4, 1973 [5 LIQUID SENSITOMETRY 0F 3,379,113 4/1968 Hosoya et a1. 96/50 R x PHOTOGRAPHIC EMULSION Inventors: Hisatoyo Kato; Hideo Takeda, both of Minami Ashigara-Machi, Japan Fuji Photo Film Co., Ltd., Kanagawa, Japan Filed: 0a. 12, 1971 Appl. No.: 188,404

Assignee:

Foreign Application Priority Data Oct. 13, 1970 Japan 45/89933 6/1972 Trcka et al 23/230 R Primary ExaminerJoseph Scovronek Att0rneySughrue, Rothwell, Mion, Zinn & Macpeak [5 7 ABSTRACT A method of performing liquid sensitometry on a liquid photographic emulsion wherein the photographic emulsion is exposed to radiation and then caused to flow in contact with a developer solution. The photographic emulsion and developer remain in distinct layers in contact with each other. During the period when the developer and emulsion flow together, the emulsion is developed by diffusion and penetration of the developer at the interface between the developer and emulsion. The optical density of the developed emulsion is continuously measured.

4 Claims, 4 Drawing Figures PATENTED DEC 4 I975 RELAT ABSO COEF RP FICIENT log E RELATIVE EXPOSURE AMOUNT LIQUID SENSITOMETRY OF PHOTOGRAPHIC EMULSION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an improvement in liquid emulsion sensi-tometry of photographic emulsion in liquid state.

2. Description of the Prior Art The ordinary sensitometry of silver halide photographic emulsion is carried out as follows:

A sample of emulsion is coated on a base support such as film paper or other fabric and dried thereon. The resulting sensitized material is cut into strips, exposed to light of graduated intensity, developed, fixed, washed and dried. The optical density of the resulting image is then measured in a demsitomet er. From the data thus obtained, various photograpic characteristics of the material can be determined. However, such tests are relatively time cn5uming,.requiring hours or even days, and thus inadquate to test and/or control the properties of emulsions by measurement of photographic characteristics during the course of manufacture. Liquid emulsion sensitometry is a rapid and simple method for determining relative densities produced upon exposure and development of photographic emulsion which is disclosed, in U.S. Pat. No. 2,590,830.

SUMMARY OF THE INVENTION -It is an object of the invention to provide an improved method of liquid emulsion sensitometry based on a different concept than U.S Pat. No. 2,590,830.

An object of the invention is to provide a method of liquid sensitometry of photographic emulsion without losing advantages of the conventional liquid emulsion sensitometry.

Another object of the invention is to provide a method of liquid emulsion sensitometry for obtaining a relation between exposure and density rapidly and easilywhile changing the quantity of exposure (i.e., the product of the length of time of the exposure and the intensity of the radiation source).

Still another object of the invention is to provide a method of liquid emulsion sensitometry without the contamination of vessel walls.

The above objects can be attained by flowing a liquid silver halide photographic emulsion and a developer solution in such a manner that they are separated into two distinct contacting layers to diffuse and penetrate the developer solution into the liquid emulsion at the interface therebetween, whereby the liquid emulsion is developed. The optical density of the developed liquid emulsion is continuously measured.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described with reference to the drawings, in which:

FIGS. la lf are views illustrating the conventional liquid sensitometry of photographic emulsion,

FIGS. 2 and 3 are views showing the apparatus for practical embodiments of the method according to the invention, and

FIG. 4 is a characteristic curve showing the photographic properties obtained by the method according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A conventional method of liquid sensitometry of 5 photographic emulsion will now be described referring to FIGS. 1a If.

A melted photographic emulsion 10 is measured by a measuring device 11, and the emulsion is introduced in a transparent vessel 12 as an inspection sample 13. Exposing the transparent vessel 12 to a light source 14, the sample 13 is exposed in a liquid state. A prescribed quantity of developer solution 15 is added to the sample, and the resulting mixture is sufficiently stirred with an agitator 16 so as to effect development. In order to stop development at the end of the desired period, a predetermined quantity of stopping solution or fixing solution 17 is added to the sample 13, and the optical density of the sample 13 is then measured in a densitometer, comprising a light source 18, a collimator l9, and a light receiver 20. By repeating the above- .mentioned operations while changing the quantity of tage that sensitometry of the photographic emulsion can be effected promptly and simply as compared with the ordinary sensitometry of an emulsion coated and dried on film, paper or other fabric, it has the following drawbacks.

Namely, the above-mentioned developing operations must be repeated, while varying the quantity of exposure, for determining the definite relation between the quantity of exposure and the density of emulsion, thus the total measurement is troublesome. Although a process is known in which the liquid emulsion sensitometry is carried out continuously by changing exposure by means of a flow tube, even in this case, due to the velocity distribution of flow, emulsions, which are exposed to various exposure levels and mixed with developer solution, are measured" together at the density measuring point in the downstream of flow tube, so that it is difficult to obtain an accurate value of density under each exposure level when the exposure is varied rapidly and continuously.

Since photographic emulsion and developer solution are to be mixed, the wall of a vessel or a tube is liable to be contaminated by emulsion, which leads to errors in the optical measurement of density, and it is necessary to clean a vessel or a tube frequently.

FIG. 2 is an apparatus. showing an embodiment of the method according to the invention. In the drawing, developer solution 51 is conducted through a tube 50 in a perfect laminar flow. A small tube 52 inserted in the upper portion A of a tube 50 and liquid emulsion 53 is extruded from tube 52 in a thread form into the central portion of the tube 50. The liquid emulsion is conducted such that it is surrounded by the developer solution while the liquid emulsion and the dveloper solution are distinctly separated. The emulsion and the developer solution are made to flow at a predetermined constant rate of flow utilizing head pressure or a metering pump.

In such a flowing condition, development of the emulsion 53 proceeds only by diffusion and penetration of the developer solution 51 into the thread emulsion The emulsion 53 is subjected to uniform radiation of desired intensity and wavelength in the samll tube 52.

Tube 52 comprises a material which is transparent to light of the wavelength to be employed in the exposure. The radiation is derived from light source 54 and controlled by a suitable intensity control device. Furthermore, since the thread emulsion 53 is carried in such a state that the relative position is fixed, or in' a socalled piston flow, no problems arise upon mixing because of the velocity distribution of flow in the tube, when exposure is changed rapidly and continuously which occurs in the conventional method.

The quantity of silver reduced by development is determined at a density measuring point B on the downstream of the tube 50 where development proceeded for an optimum developing period which was determined previously. A beam of light from a source 55 passes through collimeter 56 and is focused on the emulsion 53 through a window of tube 50, and the transmitted light or reflected light is measured by a light receiver 57.

In this apparatus, since the emulsion 53 does not come in contact with the wall of the tube 50, the tube will not be contaminated by adhesion of emulsion or the reduced silver. Therefore, there is no possibility of making errors in the optical measurement because of contamination.

Furthermore, since all the liquid is flowing, a certain time is required before blackening density appears, even when the emulsion 53 is affected by the light from a source 55, so that the light of any wavelength does not affect the density measurement, and thus can be selected optionally.

It is difficult to prove quantitatively, but the development process of this invention is more or less similar to the development process in the coated emulsion such as in conventional photographic film or paper, in which diffusion and penetration effect appear, rather than the process in the method of US. Pat. No. 2,590,830. And thus, utilizing the invention, we can determine the photographic properties in the coated emulsion without a complicated processing of ordinary photographic sensitometry.

FIG. 3 is a schematic diagram of the apparatus show-. ing another embodiment of the method according to the invention. A developer solution 61 is extruded from a discharge slot 65 onto the downwardly inclined slide surface 60 in the form ofa layer, and flows down on the slide surface under the influence of gravity. Next, a liquid emulsion layer 62 is extruded from a discharge slot 66 onto the downwardly slide surface 60. After being exposed to a predetermined quantity of illumination from a light source 67, the liquid emulsion layer 62 flows up on top of the layer 61 of the developer solution and the two then flow together down slide surface 60 separated into two distinct layers. The optical density, due to silver reduced by development, is determined by projecting light from a source 63 on a density measuring point C where development has proceeded for an optimum predetermined developing time, and measuring the transmitted light or reflected light with a light receiver 64. v

In the case in which this apparatus is used, it can be measured and all kinds of developer solutions can be used for measuring the silver halide liquid emulsion. Example:

This example was carried out by using the apparatus shown by FIG. 2.

While phenidone-hydroquinone developer (PQ developer) at C was continuously supplied into a tube 50, a high speed X-ray photographic emulsion at 30 C was extruded in a thread state from a small tube 52 into the center of tube 50. In this case, an inner diameter of the tube 50 was 2.3 mm., a diameter of the thread liquid emulsion was 0.2 mm., and a linear velocity of the thread liquid emulsion was 3.1 cm./sec. The emulsion flowing in the small tube 52 was exposed to a light source, in which the quantity of exposure was controlled by continuously changing the density of a neutral density filter.

The thread liquid emulsion 53 and the developer 51 flowed in the direction of the arrow in such a state that the solution 51 surrounded the emulsion 53, and the liquid emulsion was developed with the developer only by the diffusion and penetration of the developer into the emulsion.

At a point B'of the tube 50, where the developed emulsion flowed one minute after contact with the developer, a degree of light absorption (total incident light (reflected light transmitted light diffused light) was measured utilizing an integrating sphere. In

, this case, since the exposure was continuously changed easily understood that the device has a similar advantage as that shown in FIG. 2.

of liquid silver halide photographic emulsions can be with a lapse of time, the blackening optical density corresponding to the different exposure level was continuously obtained with a lapse of time. A wavelength of light for measuring the optical density was 600 mm.

A characteristic curve as shown in FIG. 4 was obtained which is the same result as in the conventional sensitometry using a photographic plate or photographic film.

While the invention has been particularly shown and described with reference to the preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

We claim:

1. A method of performing sensitometry of a photographic emulsion comprising:

a. causing a flow of a liquid photographic emulsion;

b. exposing said photographic emulsion to a predetermined quantity of radiation;

c. causing a flow of a developer solution such that the developer solution contacts said exposed photographic emulsion and said developer solution and said exposed photographic emulsion form two distinct layers flowing at the same velocity, whereby said exposed photographic emulsion is developed by diffusion and penetration of said developer solution into said exposed photographic emulsion at the contacting surface therebetween while in the flowing condition; and

d. continuously measuring the optical density of the developed photographic emulsion while said devel oped photographic emulsion is in its flowing condition.

2. The method of performing sensitometry as set forth in claim 1 wherein causing the flow of the liquid photographic emulsion comprises extruding said photographic emulsion.

forth in claim 2, wherein said exposing of said photographic emulsion is to a continually changing quantity of radiation, wherein said developer solution is caused to flow by extruding it from a slot on an inclined surface and allowing it to flow down said inclined surface under the influence of gravity, and wherein the photographic emulsion is extruded in the form of a layer which flows on top of the extruded developer solution. 

2. The method of performing sensitometry as set forth in claim 1 wherein causing the flow of the liquid photographic emulsion comprises extruding said photographic emulsion.
 3. The method of performing sensitometry as set forth in claim 2, wherein said exposing of said photographic emulsion is to a continually changing quantity of radiation wherein said developer solution is caused to flow in a perfect laminar flow and wherein the photographic emulsion is extruded in the form of a thread surrounded by said developer and is in contact therewith in said distinct layers.
 4. The method of performing sensitometry as set forth in claim 2, wherein said exposing of said photographic emulsion is to a continually changing quantity of radiation, wherein said developer solution is caused to flow by extruding it from a slot on an inclined surface and allowing it to flow down said inclined surface under the influence of gravity, and wherein the photographic emulsion is extruded in the form of a layer which flows on top of the extruded developer solution. 